Method for use with a speakerphone system that corrects for mechanical vibrations

ABSTRACT

A method for substantially eliminating the effect of mechanical vibration on an audio input to a speakerphone system is provided herein, the method comprising: receiving mechanical vibrations and an input sound acoustic signal at a microphone (mic); converting the received mechanical vibrations and input sound acoustic signal into an input sound electrical signal, and outputting the same as a mic output signal; receiving mechanical vibrations at a mechanical vibration sensor (MVS); converting the received mechanical vibrations into a mechanical vibration error signal, and outputting the same as an MVS output signal; and generating a speakerphone system output signal by subtracting the MVS output signal from the mic output signal.

CROSS REFERENCE TO RELATED APPLICATIONS

Related subject matter is disclosed in co-pending U.S. Non-provisionalpatent application Ser. No. 16/571,439, filed Sep. 16, 2019, Crestonmatter No. CP00467-00; U.S. Non-provisional patent application Ser. No.16/571,498, filed Sep. 16, 2019, Creston matter No. CP00524-00; U.S.Non-provisional patent application Ser. No. 16/571,667, filed Sep. 16,2019, Creston matter No. CP00525-00; U.S. Non-provisional patentapplication Ser. No. 16/571,894, filed Sep. 16, 2019, Creston matter No.CP00527-00; and U.S. Non-provisional patent application Ser. No.16/572,004, filed Sep. 16, 2019, Creston matter No. CP00528-00, theentire contents of all of which are expressly incorporated herein byreference.

BACKGROUND Technical Field

The embodiments described herein relate generally to speakerphonesystems, and more specifically to systems, methods, and modes forsubstantially or completely eliminating mechanical vibration energy froma loudspeaker in the speakerphone that is converted to acousticalsignals that can be acquired by a microphone as an error signal in thespeakerphone.

Background Art

There are many different types of speakerphone systems currently beingused today in the home, office, and other enterprise locations. Many ofthese currently available systems include at least one loudspeaker andat least microphone in the same package. Unfortunately speakers, bythere very nature, vibrate when electrical signals are applied to themagnetic transducer and the cone moves to replicate as sound waves theelectrical signals that were received. In some cases, the vibrations canbe transferred to the package or case in which the speakerphone systemis enclosed, and the at least one microphone can acquire such mechanicalvibrations and convert them to electrical sound signals. Since theseacoustical signals are not true voice signals, they are noise, anddegrade the performance of the speakerphone system.

Accordingly, a need has arisen for systems, methods, and modes forsubstantially or completely eliminating mechanical vibration energy fromthe loudspeaker that is converted to acoustical signals that can beacquired by a microphone as an error signal in the speakerphone.

SUMMARY

It is an object of the embodiments to substantially solve at least theproblems and/or disadvantages discussed above, and to provide at leastone or more of the advantages described below.

It is therefore a general aspect of the embodiments to provide systems,methods, and modes for substantially or completely eliminatingmechanical vibration energy from the loudspeaker that is converted toacoustical signals that can be acquired by a microphone as an errorsignal in the speakerphone that will obviate or minimize problems of thetype previously described.

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used to limit the scope of the claimed subject matter.

Further features and advantages of the aspects of the embodiments, aswell as the structure and operation of the various embodiments, aredescribed in detail below with reference to the accompanying drawings.It is noted that the aspects of the embodiments are not limited to thespecific embodiments described herein. Such embodiments are presentedherein for illustrative purposes only. Additional embodiments will beapparent to persons skilled in the relevant art(s) based on theteachings contained herein.

According to a first aspect of the embodiments, a speakerphone system isprovided, comprising: at least one mechanical vibration sensor adaptedto convert mechanical vibrations in a speakerphone enclosure (enclosure)to a mechanical vibration error signal, and output the same as an MVSoutput signal; at least one microphone adapted to convert an input soundacoustic signal into an input sound electrical signal and to output thesame as a mic output signal; and circuitry adapted to subtract the MVSoutput signal from the mic output signal and output the resultant signalas a speakerphone output signal.

According to the first aspect of the embodiments the circuitrycomprises: a first receiver adapted to receive the output of the MVS; asecond receiver adapted to receive the output of the mic; and additionalcircuitry adapted to perform the subtraction of the MVS output signalfrom the mic output signal.

According to the first aspect of the embodiments system furthercomprises: a first analog to digital converter adapted to digitize anoutput of the first receiver, and forward the same to the additionalcircuitry; and a second analog to digital converter adapted to digitizean output of the second receiver, and forward the same to the additionalcircuitry.

According to the first aspect of the embodiments the additionalcircuitry comprises: a signal processor adapted to perform thesubtraction of the MVS output signal from the mic output signal.

According to the first aspect of the embodiments the additionalcircuitry comprises: analog circuitry adapted to perform the subtractionof the MVS output signal from the mic output signal.

According to the first aspect of the embodiments the first receivercomprises: a first analog signal line receiver adapted to receive theoutput of the MVS; an amplifier adapted to amplify substantially onlyaudio frequency signals; and a filter adapted to pass substantially onlyaudio frequency signals.

According to the first aspect of the embodiments the second receivercomprises: a second analog signal line receiver adapted to receive theoutput of the mic; an amplifier adapted to amplify substantially onlyaudio frequency signals; and a filter adapted to pass substantially onlyaudio frequency signals.

According to the first aspect of the embodiments the MVS is one of amic, an accelerometer, and a microelectromechanical system (MEMs)integrated accelerometer.

According to the first aspect of the embodiments wherein the systemfurther comprises: at least one loudspeaker adapted to generate anoutput sound that is broadcast into a volume of space exterior to thatof the enclosure, and wherein the broadcast output sound generates themechanical vibrations on the enclosure.

According to the first aspect of the embodiments wherein the at leastone loudspeaker is further adapted to generate backscatter sound that isbroadcast into a volume of space within the enclosure, and wherein themechanical vibrations are generated through a combination of the outputsound broadcast externally to the enclosure and the backscatter soundbroadcast into the volume of the enclosure.

According to the first aspect of the embodiments wherein the circuitryis further adapted to store a plurality of calibration factorscomprising—α, an input-to-output transformation coefficient for acousticsound signals in regard to the mic (mic acoustic transformationcoefficient/calibration factor), β, an input-to-output transformationcoefficient for mechanical vibration signals generated by a loudspeakerin regard to the mic (mic vibration transformationcoefficient/calibration factor), γ, an input-to-output transformationcoefficient for acoustic sound signals in regard to the MVS (MVSacoustic transformation coefficient/calibration factor), and β, aninput-to-output transformation coefficient for mechanical vibrationsignals generated by the loudspeaker in regard to the MVS (MVS vibrationtransformation coefficient/calibration factor).

According to the first aspect of the embodiments the system furthercomprises: a first network interface adapted to bidirectionallycommunicate with the circuitry of the speakerphone and one or moreexternal devices; and an external calibration apparatus adapted tocalibrate the system and generate the plurality of calibration factors.

According to the first aspect of the embodiments wherein the externalcalibration apparatus comprises: a calibration loudspeaker; a secondnetwork interface adapted to bidirectionally communicate with the firstnetwork interface; a processor circuit that includes a memory device; acommunications circuit adapted to facilitate transfers of data andcommands between the processor circuit, the memory device, and thesecond network interface; and a first signal generator adapted togenerate one or more acoustic audio test signals that can be broadcastby the calibration loudspeaker and received by the mic and the MVS, andfurther wherein the processor circuit is adapted to determine thetransformation coefficients α and γ based on data generated by thegenerated one or more acoustic audio test signals.

According to the first aspect of the embodiments wherein the externalcalibration apparatus further comprises: a second signal generatoradapted to generate one or more electrical audio test signals that canbe broadcast by the at least one loudspeaker in the speakerphone thatgenerate test mechanical vibrations that are received by the mic andMVS, and further wherein the processor circuit is adapted to determinethe transformation coefficients β and δ based on data generated by thegenerated test mechanical vibration signals.

According to the first aspect of the embodiments wherein the one or moreexternal devices comprise one or more devices interconnected with thesystem by one or more of a local area network, a wide area network, anInternet, a cellular communications network, a satellite communicationsnetwork, a landline network, and a dedicated speakerphone network.

According to the first aspect of the embodiments the one or more devicesincludes one or more of a speakerphone system and a server computer.

According to the first aspect of the embodiments an output of the mic inregard to an input of an acoustic sound signal can be characterized bythe application of the transfer coefficient α to the input acousticsound signal, an output of the MVS in regard to an input of a mechanicalvibration signal generated by the loudspeaker can be characterized bythe application of the transfer coefficient β to the input mechanicalvibration signal, an output of the MVS in regard to an input of theacoustic sound signal can be characterized by the application of thetransfer coefficient γ to the input acoustic sound signal, and an outputof the mic in regard to an input of the mechanical vibration signalgenerated by the loudspeaker can be characterized by the application ofthe transfer coefficient δ to the mechanical vibrations signal.

According to a second aspect of the embodiments. a speakerphone systemis provided, comprising: at least one loudspeaker, the loudspeakeradapted to generate mechanical vibrations on an enclosure of the system;at least one microphone (mic) adapted to convert an input sound acousticsignal into an input sound electrical signal and adapted to convert themechanical vibrations into a mechanical vibrations electrical signal,and to output both of the input sound electrical signal and themechanical vibrations electrical signal as a mic output signal; at leastone mechanical vibration sensor (MVS) adapted to convert the mechanicalvibrations to a mechanical vibration error signal to output themechanical vibration error signal as an MVS output signal; and circuitryadapted to subtract the MVS output signal from the mic output signal andoutput the resultant signal as a speakerphone output signal.

According to the second aspect of the embodiments the circuitrycomprises: a first receiver adapted to receive the output of themechanical vibration sensor; a second receiver adapted to receive theoutput of the mic; and additional circuitry adapted to perform thesubtraction of the MVS output signal from the mic output signal.

According to the second aspect of the embodiments the system furthercomprises: a first analog to digital converter adapted to digitize anoutput of the first receiver, and forward the same to the additionalcircuitry; and a second analog to digital converter adapted to digitizean output of the second receiver, and forward the same to the additionalcircuitry.

According to the second aspect of the embodiments the additionalcircuitry comprises: a digital signal processor adapted to perform thesubtraction of the MVS output signal from the mic output signal.

According to the second aspect of the embodiments the additionalcircuitry comprises: analog circuitry adapted to perform the subtractionof the MVS output signal from the mic output signal.

According to the second aspect of the embodiments the first receivercomprises: a first analog signal line receiver adapted to receive theoutput of the MVS; an amplifier adapted to amplify substantially onlyaudio frequency signals; and a filter adapted to pass substantially onlyaudio frequency signals.

According to the second aspect of the embodiments the second receivercomprises: a second analog signal line receiver adapted to receive theoutput of the mic; an amplifier adapted to amplify substantially onlyaudio frequency signals; and a filter adapted to pass substantially onlyaudio frequency signals.

According to the second aspect of the embodiments the MVS is one of amic, an accelerometer, and a microelectromechanical system (MEMs)integrated accelerometer.

According to the second aspect of the embodiments the at least oneloudspeaker is adapted to generate an output sound that is broadcastinto a volume of space exterior to that of the enclosure, and whereinthe broadcast output sound generates the mechanical vibrations on theenclosure.

According to the second aspect of the embodiments the at least oneloudspeaker is further adapted to generate backscatter sound that isbroadcast into a volume of space within the enclosure, and wherein themechanical vibrations are generated through a combination of the outputsound broadcast externally to the enclosure and the backscatter soundbroadcast into the volume of the enclosure.

According to the second aspect of the embodiments the circuitry isfurther adapted to store a plurality of calibration factorscomprising—α, an input-to-output transformation coefficient for acousticsound signals in regard to the mic (mic acoustic transformationcoefficient/calibration factor), β, an input-to-output transformationcoefficient for mechanical vibration signals generated by a loudspeakerin regard to the mic (mic vibration transformationcoefficient/calibration factor), γ, an input-to-output transformationcoefficient for acoustic sound signals in regard to the MVS (MVSacoustic transformation coefficient/calibration factor), and δ, aninput-to-output transformation coefficient for mechanical vibrationsignals generated by the loudspeaker in regard to the MVS (MVS vibrationtransformation coefficient/calibration factor).

According to the second aspect of the embodiments the circuitry isfurther adapted to receive a far end audio signal prior to beingbroadcast by the at least one loudspeaker, and wherein the circuitry isfurther adapted to generate the speakerphone output signal according tothe following equation—second speakerphone output signal=((MIC outputsignal−(β×far end audio signal))−MVS output signal)/α.

According to the second aspect of the embodiments the MVS is furtheradapted to convert the input sound acoustic signal into an input sounderror signal (126″), and to output both the mechanical vibration errorsignal and the input sound error signal as an MVS output signal.

According to the second aspect of the embodiments the circuitry isfurther adapted to receive a far end audio signal prior to beingbroadcast by the at least one loudspeaker, and wherein the circuitry isfurther adapted to generate the speakerphone output signal according tothe following equation—second speakerphone output signal=((MIC outputsignal−(β×far end audio signal))−MVS output signal)/α.

According to the second aspect of the embodiments the system furthercomprises: a first network interface adapted to bidirectionallycommunicate with the circuitry of the speakerphone and one or moreexternal devices; and an external calibration apparatus adapted tocalibrate the system and generate the plurality of calibration factors.

According to the second aspect of the embodiments the externalcalibration apparatus comprises: a calibration loudspeaker; a secondnetwork interface adapted to bidirectionally communicate with the firstnetwork interface; a processor circuit that includes a memory device; acommunications circuit adapted to facilitate transfers of data andcommands between the processor circuit, the memory device, and thesecond network interface; and a first signal generator adapted togenerate one or more acoustic audio test signals that can be broadcastby the calibration loudspeaker and received by the mic and the MVS, andfurther wherein the processor circuit is adapted to determine thetransformation coefficients α and γ based on data generated by thegenerated one or more acoustic audio test signals.

According to the second aspect of the embodiments the externalcalibration apparatus further comprises: a second signal generatoradapted to generate one or more electrical audio test signals that canbe broadcast by the at least one loudspeaker in the speakerphone thatgenerate test mechanical vibrations that are received by the mic andMVS, and further wherein the processor circuit is adapted to determinethe transformation coefficients β and δ based on data generated by thegenerated test mechanical vibration signals.

According to the second aspect of the embodiments the one or moreexternal devices comprise one or more devices interconnected with thesystem by one or more of a local area network, a wide area network, anInternet, a cellular communications network, a satellite communicationsnetwork, a landline network, and a dedicated speakerphone network.

According to the second aspect of the embodiments the one or moredevices includes one or more of a speakerphone system and a servercomputer.

According to the second aspect of the embodiments an output of the micin regard to an input of an acoustic sound signal can be characterizedby the application of the transfer coefficient α to the input acousticsound signal, an output of the MVS in regard to an input of a mechanicalvibration signal generated by the loudspeaker can be characterized bythe application of the transfer coefficient β to the input mechanicalvibration signal, an output of the MVS in regard to an input of theacoustic sound signal can be characterized by the application of thetransfer coefficient γ to the input acoustic sound signal, and an outputof the mic in regard to an input of the mechanical vibration signalgenerated by the loudspeaker can be characterized by the application ofthe transfer coefficient δ to the mechanical vibrations signal.

According to a third aspect of the embodiments, a speakerphone network(network) is provided, comprising: at least two speakerphones adapted tobidirectionally communicate with each other through an electronicscommunication network, wherein the network comprises one or more of alocal area network, a wide area network, a dedicated speakerphonenetwork, a cellular communications network, a satellite communicationsnetwork, a landline telephone network, and an Internet network(Internet), and wherein the speakerphone comprises at least onemechanical vibration sensor (MVS) adapted to convert mechanicalvibrations in a speakerphone enclosure (enclosure) to a mechanicalvibration error signal, and output the same as an MVS output signal; atleast one microphone (mic) adapted to convert an input sound acousticsignal into an input sound electrical signal and to output the same as amic output signal; and circuitry adapted to subtract the MVS outputsignal from the mic output signal and output the resultant signal as aspeakerphone output signal.

According to a fourth aspect of the embodiments, a speakerphone network(network) is provided comprising: at least two speakerphones adapted tobidirectionally communicate with each other through an electronicscommunication network, wherein the network comprises one or more of alocal area network, a wide area network, a dedicated speakerphonenetwork, a cellular communications network, a satellite communicationsnetwork, a landline telephone network, and an Internet network(Internet), and wherein the speakerphone comprises at least oneloudspeaker adapted to generate mechanical vibrations on an enclosure ofthe system; at least one microphone (mic) adapted to convert an inputsound acoustic signal into an input sound electrical signal and adaptedto convert the mechanical vibrations into a mechanical vibrationselectrical signal, and to output both of the input sound electricalsignal and the mechanical vibrations electrical signal as a mic outputsignal; at least one mechanical vibration sensor (MVS) adapted toconvert the mechanical vibrations to a mechanical vibration error signalto output the mechanical vibration error signal as an MVS output signal;and circuitry adapted to subtract the MVS output signal from the micoutput signal and output the resultant signal as a speakerphone outputsignal.

According to a fifth aspect of the embodiments a method forsubstantially eliminating the effect of mechanical vibration on an audioinput to a speakerphone system is provided comprising: receiving aninput sound acoustic signal at a microphone (mic); converting thereceived input sound acoustic signal into an input sound electricalsignal, and outputting the same as a mic output signal; receivingmechanical vibrations at a mechanical vibration sensor (MVS); convertingthe received mechanical vibrations into a mechanical vibration errorsignal, and outputting the same as an MVS output signal; and generatinga speakerphone system output signal by subtracting the MVS output signalfrom the mic output signal.

According to the fifth aspect of the embodiments the step of generatinga speakerphone output signal comprises: receiving the output of the MVSat a first receiver; receiving the output of the mic at a secondreceiver; and subtracting the MVS output signal from the mic outputsignal using additional circuitry.

According to the fifth aspect of the embodiments the step of subtractingcomprises: digitizing the received outputs of the first receiver andsecond receiver; and subtracting the digitized MVS output signal fromthe digitized mic output signal using a digital signal processor.

According to the fifth aspect of the embodiments the step of subtractingcomprises: subtracting the MVS output signal from the mic output signalusing analog circuitry.

According to the fifth aspect of the embodiments the MVS is one of amic, an accelerometer, and a microelectromechanical system (MEMs)integrated accelerometer.

According to the fifth aspect of the embodiments the method furthercomprises: broadcasting an output sound from at least one loudspeakerinto a volume of space exterior to that of the enclosure; and generatingthe mechanical vibrations on the enclosure resulting from the broadcastoutput sound.

According to the fifth aspect of the embodiments the method furthercomprises: broadcasting a backscatter sound into a volume of spacewithin the enclosure; and generating the mechanical vibrations resultingfrom a combination of the output sound broadcast externally to theenclosure and the backscatter sound broadcast into the volume of theenclosure.

According to the fifth aspect of the embodiments the method furthercomprises: storing in memory a plurality of calibration factors, whereinthe plurality of calibration factors comprises—α, an input-to-outputtransformation coefficient for acoustic sound signals in regard to themic (mic acoustic transformation coefficient/calibration factor), β, aninput-to-output transformation coefficient for mechanical vibrationsignals generated by a loudspeaker that is part of the speakerphone inregard to the mic (mic vibration transformation coefficient/calibrationfactor), γ, an input-to-output transformation coefficient for acousticsound signals in regard to the MVS (MVS acoustic transformationcoefficient/calibration factor), and δ, an input-to-outputtransformation coefficient for mechanical vibration signals generated bythe loudspeaker in regard to the MVS (MVS vibration transformationcoefficient/calibration factor).

According to the fifth aspect of the embodiments the method furthercomprises: performing bidirectional communications between a firstnetwork interface that is part of the speakerphone and one or moreexternal devices.

According to the fifth aspect of the embodiments the step of performingbidirectional communications comprises: communicating with an externalcalibration system adapted to generate the plurality of calibrationfactors.

According to the fifth aspect of the embodiments the externalcalibration apparatus comprises—a calibration loudspeaker; a secondnetwork interface adapted to bidirectionally communicate with the firstnetwork interface; a processor circuit that includes a memory device; acommunications circuit adapted to facilitate transfers of data andcommands between the processor circuit, the memory device, and thesecond network interface; and a first signal generator adapted togenerate one or more acoustic audio test signals.

According to the fifth aspect of the embodiments the method furthercomprises: generating the one or more acoustic audio test signals by thefirst signal generator that is broadcast by the calibration loudspeakerand received by the mic and the MVS, and determining the transformationcoefficients α and γ by the processor based on data generated by thegenerated one or more acoustic audio test signals.

According to the fifth aspect of the embodiments the calibrationapparatus further comprises—a second signal generator adapted togenerate one or more electrical audio test signal.

According to the fifth aspect of the embodiments the method furthercomprises: generating the one or more electrical audio test signals bythe second signal generator that is broadcast by the at least oneloudspeaker in the speakerphone that generates test mechanicalvibrations that are received by the mic and MVS; and determining thetransformation coefficients β and δ by the processor based on datagenerated by the generated test mechanical vibration signals.

According to the fifth aspect of the embodiments the one or moreexternal devices comprise one or more devices interconnected with thesystem by one or more of a local area network, a wide area network, anInternet, a cellular communications network, a satellite communicationsnetwork, a landline network, and a dedicated speakerphone network.

According to the fifth aspect of the embodiments the one or more devicesincludes one or more of a speakerphone system and a server computer.

According to the fifth aspect of the embodiments an output of the mic inregard to an input of an acoustic sound signal can be characterized bythe application of the transfer coefficient α to the input acousticsound signal, an output of the MVS in regard to an input of a mechanicalvibration signal generated by the loudspeaker can be characterized bythe application of the transfer coefficient β to the input mechanicalvibration signal, an output of the MVS in regard to an input of theacoustic sound signal can be characterized by the application of thetransfer coefficient γ to the input acoustic sound signal, and an outputof the mic in regard to an input of the mechanical vibration signalgenerated by the loudspeaker can be characterized by the application ofthe transfer coefficient δ to the mechanical vibrations signal.

According to a sixth aspect of the embodiments, a method forsubstantially eliminating the effect of mechanical vibration on an audioinput to a speakerphone system is provided comprising: receivingmechanical vibrations and an input sound acoustic signal at a microphone(mic); converting the received mechanical vibrations and input soundacoustic signal into an input sound electrical signal, and outputtingthe same as a mic output signal; receiving mechanical vibrations at amechanical vibration sensor (MVS); converting the received mechanicalvibrations into a mechanical vibration error signal, and outputting thesame as an MVS output signal; and generating a speakerphone systemoutput signal by subtracting the MVS output signal from the mic outputsignal.

According to the sixth aspect of the embodiments the step of generatinga speakerphone output signal comprises: receiving the output of the MVSat a first receiver; receiving the output of the mic at a secondreceiver; and subtracting the MVS output signal from the mic outputsignal using additional circuitry.

According to the sixth aspect of the embodiments the step of subtractingcomprises: digitizing the received outputs of the first receiver andsecond receiver; and subtracting the digitized MVS output signal fromthe digitized mic output signal using a digital signal processor.

According to the sixth aspect of the embodiments the step of subtractingcomprises: subtracting the MVS output signal from the mic output signalusing analog circuitry.

According to the sixth aspect of the embodiments the MVS is one of amic, an accelerometer, and a microelectromechanical system (MEMs)integrated accelerometer.

According to the sixth aspect of the embodiments the method furthercomprises: broadcasting an output sound from at least one loudspeakerinto a volume of space exterior to that of the enclosure; and generatingthe mechanical vibrations on the enclosure resulting from the broadcastoutput sound.

According to the sixth aspect of the embodiments the method furthercomprises: broadcasting a backscatter sound into a volume of spacewithin the enclosure; and generating the mechanical vibrations resultingfrom a combination of the output sound broadcast externally to theenclosure and the backscatter sound broadcast into the volume of theenclosure.

According to the sixth aspect of the embodiments the method furthercomprises: storing in memory a plurality of calibration factors, whereinthe plurality of calibration factors comprises—α, an input-to-outputtransformation coefficient for acoustic sound signals in regard to themic (mic acoustic transformation coefficient/calibration factor), β, aninput-to-output transformation coefficient for mechanical vibrationsignals generated by a loudspeaker that is part of the speakerphone inregard to the mic (mic vibration transformation coefficient/calibrationfactor), γ, an input-to-output transformation coefficient for acousticsound signals in regard to the MVS (MVS acoustic transformationcoefficient/calibration factor), and δ, an input-to-outputtransformation coefficient for mechanical vibration signals generated bythe loudspeaker in regard to the MVS (MVS vibration transformationcoefficient/calibration factor).

According to the sixth aspect of the embodiments the method furthercomprises: receiving a far end audio signal prior to being broadcast bythe loudspeaker; and generating the speakerphone output signal accordingto the following equation—second speakerphone output signal=((MIC outputsignal−(β×far end audio signal))−MVS output signal)/α.

According to the sixth aspect of the embodiments the method furthercomprises: converting the input sound acoustic signal into an inputsound error signal (126″); and outputting both the mechanical vibrationerror signal and the input sound error signal as an MVS output signal.

According to the sixth aspect of the embodiments the method furthercomprises: receiving a far end audio signal prior to being broadcast bythe loudspeaker; and generating the speakerphone output signal accordingto the following equation—second speakerphone output signal=((MIC outputsignal−(β×far end audio signal))−MVS output signal)/α.

According to the sixth aspect of the embodiments the method furthercomprises: performing bidirectional communications between a firstnetwork interface that is part of the speakerphone and one or moreexternal devices.

According to the sixth aspect of the embodiments the step of performingbidirectional communications comprises: communicating with an externalcalibration system adapted to generate the plurality of calibrationfactors.

According to the sixth aspect of the embodiments the externalcalibration apparatus comprises—a calibration loudspeaker; a secondnetwork interface adapted to bidirectionally communicate with the firstnetwork interface; a processor circuit that includes a memory device; acommunications circuit adapted to facilitate transfers of data andcommands between the processor circuit, the memory device, and thesecond network interface; and a first signal generator adapted togenerate one or more acoustic audio test signals.

According to the sixth aspect of the embodiments the method furthercomprises: generating the one or more acoustic audio test signals by thefirst signal generator that is broadcast by the calibration loudspeakerand received by the mic and the MVS, and determining the transformationcoefficients α and γ by the processor based on data generated by thegenerated one or more acoustic audio test signals.

According to the sixth aspect of the embodiments the calibrationapparatus further comprises—a second signal generator adapted togenerate one or more electrical audio test signals.

According to the sixth aspect of the embodiments the method furthercomprises: generating the one or more electrical audio test signals bythe second signal generator that is broadcast by the at least oneloudspeaker in the speakerphone that generates test mechanicalvibrations that are received by the mic and MVS; and determining thetransformation coefficients β and δ by the processor based on datagenerated by the generated test mechanical vibration signals.

According to the sixth aspect of the embodiments the one or moreexternal devices comprise one or more devices interconnected with thesystem by one or more of a local area network, a wide area network, anInternet, a cellular communications network, a satellite communicationsnetwork, a landline network, and a dedicated speakerphone network.

According to the sixth aspect of the embodiments the one or more devicesincludes one or more of a speakerphone system and a server computer.

According to the sixth aspect of the embodiments an output of the mic inregard to an input of an acoustic sound signal can be characterized bythe application of the transfer coefficient α to the input acousticsound signal, an output of the MVS in regard to an input of a mechanicalvibration signal generated by the loudspeaker can be characterized bythe application of the transfer coefficient β to the input mechanicalvibration signal, an output of the MVS in regard to an input of theacoustic sound signal can be characterized by the application of thetransfer coefficient γ to the input acoustic sound signal, and an outputof the mic in regard to an input of the mechanical vibration signalgenerated by the loudspeaker can be characterized by the application ofthe transfer coefficient δ to the mechanical vibrations signal.

According to a seventh aspect of the embodiments, a speakerphonecalibration system (system) is provided, comprising: a calibration unitadapted to generate at least one test signal, and further adapted todetermine at least one calibration factor in response to at least onetest signal, and wherein a first calibration factor characterizes aspeakerphone system under test in regard to mechanical vibrationsgenerated in the speakerphone system under test, the mechanicalvibrations caused by a first test signal.

According to the seventh aspect of the embodiments, the calibration unitfurther comprises: a first processor adapted to generate the first testsignal; and a first communications interface adapted to transmit thefirst test signal to the speakerphone system under test, and wherein thespeakerphone system under test comprises—a microphone (mic) adapted toreceive acoustic energy and convert the same to a mic electrical signal;a second communications interface adapted to receive the first testsignal; a second processor; a loudspeaker adapted to receive anelectrical audio signal and broadcast the same as an acoustic signal; amechanical vibration sensor adapted to sense vibrations in an enclosureof the speakerphone system and convert the same to an MVS electricalsignal.

According to the seventh aspect of the embodiments the second processorof the speakerphone system under test is adapted to process the firsttest signal and generate a first audio test signal based on the firsttest signal, and transmit the same to the loudspeaker, the loudspeakeris adapted to receive the first audio test signal, broadcast the same asa first acoustic signal, and to generate a first set of vibrations on anenclosure of the speakerphone system under test based on the first testsignal, and the MVS is adapted to sense the first set of vibrations onthe enclosure of the speakerphone system based on the first test signal,and to convert the same to a first MVS electrical signal.

According to the seventh aspect of the embodiments the calibration unitis further adapted to generate an input-to-output transformationcoefficient for mechanical vibration signals generated by theloudspeaker in regard to the mechanical vibration sensor (calibrationfactor δ), the calibration factor δ based on a comparison between thefirst test signal and the first MVS electrical signal.

According to the seventh aspect of the embodiments the mic is adapted tosense the first set of vibrations on the enclosure of the speakerphonesystem based on the first test signal, and to convert the same to an micelectrical signal.

According to the seventh aspect of the embodiments the calibration unitis further adapted to generate an input-to-output transformationcoefficient for mechanical vibration signals generated by theloudspeaker in regard to the mic (calibration factor β), the calibrationfactor β based on a comparison between the first test signal and thefirst mic electrical signal.

According to the seventh aspect of the embodiments the calibration unitfurther comprises: a calibration loudspeaker, and wherein thecalibration unit is adapted to generate a second test signal that istransmitted to the calibration loudspeaker, wherein the calibrationloudspeaker is adapted to receive the second test signal and broadcast asecond acoustic test signal, and wherein the second acoustic test signalgenerates a second set of vibrations, and the MVS is adapted to sensethe second set of vibrations on the enclosure of the speakerphone systembased on the second test signal, and to convert the same to a second MVSelectrical signal.

According to the seventh aspect of the embodiments the calibration unitis further adapted to generate an input-to-output transformationcoefficient for acoustic sound signals generated by the calibrationloudspeaker in regard to the mechanical vibration sensor (calibrationfactor γ), the calibration factor γ based on a comparison between thesecond test signal and the second MVS electrical signal.

According to the seventh aspect of the embodiments the mic is adapted tosense the second set of vibrations on the enclosure of the speakerphonesystem based on the second test signal, and to convert the same to asecond mic electrical signal.

According to the seventh aspect of the embodiments the calibration unitis further adapted to generate an input-to-output transformationcoefficient for acoustic sound signals generated by the calibrationloudspeaker in regard to the mic (calibration factor α), the calibrationfactor α based on a comparison between the second test signal and thesecond mic electrical signal.

According to an eighth aspect of the embodiments, a speakerphone systemis provided comprising: a processor adapted to generate at least onetest signal, and further adapted to determine at least one calibrationfactor in response to at least one test signal, and wherein a firstcalibration factor characterizes the speakerphone system duringcalibration in regard to mechanical vibrations generated in thespeakerphone system under test, the mechanical vibrations caused by afirst test signal; a first communications interface adapted to transmitthe first test signal to the speakerphone system under test, and whereinthe speakerphone system under test comprises—a microphone (mic) adaptedto receive acoustic energy and convert the same to a mic electricalsignal; a second communications interface adapted to receive the firsttest signal; a second processor; a loudspeaker adapted to receive anelectrical audio signal and broadcast the same as an acoustic signal; amechanical vibration sensor adapted to sense vibrations in an enclosureof the speakerphone system and convert the same to an MVS electricalsignal.

According to the eighth aspect of the embodiments, the second processorof the speakerphone system under test is adapted to process the firsttest signal and generate a first audio test signal based on the firsttest signal, and transmit the same to the loudspeaker, the loudspeakeris adapted to receive the first audio test signal, broadcast the same asa first acoustic signal, and to generate a first set of vibrations on anenclosure of the speakerphone system under test based on the first testsignal, and the MVS is adapted to sense the first set of vibrations onthe enclosure of the speakerphone system based on the first test signal,and to convert the same to a first MVS electrical signal.

According to the eighth aspect of the embodiments the calibration unitis further adapted to generate an input-to-output transformationcoefficient for mechanical vibration signals generated by theloudspeaker in regard to the mechanical vibration sensor (calibrationfactor δ), the calibration factor δ based on a comparison between thefirst test signal and the first MVS electrical signal.

According to the eighth aspect of the embodiments the mic is adapted tosense the first set of vibrations on the enclosure of the speakerphonesystem based on the first test signal, and to convert the same to an micelectrical signal.

According to the eighth aspect of the embodiments the calibration unitis further adapted to generate an input-to-output transformationcoefficient for mechanical vibration signals generated by theloudspeaker in regard to the mic (calibration factor β), the calibrationfactor β based on a comparison between the first test signal and thefirst mic electrical signal.

According to the eighth aspect of the embodiments the calibration unitfurther comprises: a calibration loudspeaker, and wherein thecalibration unit is adapted to generate a second test signal that istransmitted to the calibration loudspeaker, wherein the calibrationloudspeaker is adapted to receive the second test signal and broadcast asecond acoustic test signal, and wherein the second acoustic test signalgenerates a second set of vibrations, and the MVS is adapted to sensethe second set of vibrations on the enclosure of the speakerphone systembased on the second test signal, and to convert the same to a second MVSelectrical signal.

According to the eighth aspect of the embodiments the calibration unitis further adapted to generate an input-to-output transformationcoefficient for acoustic sound signals generated by the calibrationloudspeaker in regard to the mechanical vibration sensor (calibrationfactor γ), the calibration factor γ based on a comparison between thesecond test signal and the second MVS electrical signal.

According to the eighth aspect of the embodiments the mic is adapted tosense the second set of vibrations on the enclosure of the speakerphonesystem based on the second test signal, and to convert the same to asecond mic electrical signal.

According to the eighth aspect of the embodiments the calibration unitis further adapted to generate an input-to-output transformationcoefficient for acoustic sound signals generated by the calibrationloudspeaker in regard to the mic (calibration factor α), the calibrationfactor α based on a comparison between the second test signal and thesecond mic electrical signal.

According to a ninth aspect of the embodiments, a method for calibratinga speakerphone system under test is provided comprising; connecting acalibration unit to the speakerphone system under test (SSUT) via acommunications interface, and wherein the SSUT further comprises aloudspeaker, microphone (mic), and mechanical vibration sensor (MVS);generating a first test signal by the calibration unit and transmittingthe same to the SSUT; generating a first set of mechanical vibrations inresponse to the first test signal in the SSUT; and determining acalibration factor in regard to the first test signal and first set ofmechanical vibrations by the calibration unit.

According to the ninth aspect of the embodiments, the step ofdetermining a calibration factor in regard to the first test signal andfirst set of mechanical vibrations by the calibration unit comprises:receiving the first test signal at the SSUT, and processing the same;generating a first audio signal based on the first test signal, and thenoutputting the same to the loudspeaker; broadcasting a first acousticsignal by the loudspeaker, wherein the broadcast first acoustic signalgenerates the first set of mechanical vibrations on an enclosure of theSSUT; receiving the first set of mechanical vibrations at the MVS;converting the first set of mechanical vibrations by the MVS into afirst MVS electrical signal; and generating an input-to-outputtransformation coefficient for mechanical vibration signals generated bythe loudspeaker in regard to the MVS (calibration factor δ), wherein thecalibration factor δ is based on a comparison between the first testsignal and the first MVS electrical signal.

According to the ninth aspect of the embodiments the step of generatingthe calibration factor δ comprises: receiving the first MVS electricalsignal at the calibration unit; comparing the first MVS electricalsignal with the first test signal; and generating the calibration factorδ based on the results of the comparison.

According to the ninth aspect of the embodiments the step of comparingcomprises: comparing the first MVS electrical signal and the first testsignal on the basis of frequency versus amplitude; and determining thecalibration factor δ as a function of amplitude versus frequency,

According to the ninth aspect of the embodiments the step of determiningthe calibration factor δ comprises: determining a difference between thefirst MVS electrical signal and the first test signal wherein thecalibration factor δ comprises a set of discrete amplitude factors atpredetermined frequency points, such that the amplitude factors can bemultiplied against a new output of the MVS at the predeterminedfrequency points.

According to the ninth aspect of the embodiments the step of determininga calibration factor in regard to the first test signal and first set ofmechanical vibrations by the calibration unit comprises: receiving thefirst test signal at the SSUT, and processing the same; generating afirst audio signal based on the first test signal, and then outputtingthe same to the loudspeaker; broadcasting a first acoustic signal by theloudspeaker, wherein the broadcast first acoustic signal generates thefirst set of mechanical vibrations on an enclosure of the SSUT;receiving the first set of mechanical vibrations at the mic; convertingthe first set of mechanical vibrations by the mic into a first micelectrical signal; and generating an input-to-output transformationcoefficient for mechanical vibration signals generated by theloudspeaker in regard to the mic (calibration factor β), wherein thecalibration factor β is based on a comparison between the first testsignal and the first mic electrical signal.

According to the ninth aspect of the embodiments the step of generatingthe calibration factor β comprises: receiving the first mic electricalsignal at the calibration unit; comparing the first mic electricalsignal with the first test signal; and generating the calibration factorβ based on the results of the comparison.

According to the ninth aspect of the embodiments the step of comparingcomprises: comparing the first mic electrical signal and the first testsignal on the basis of frequency versus amplitude; and determining thecalibration factor β as a function of amplitude versus frequency.

According to the ninth aspect of the embodiments the step of determiningthe calibration factor comprises: determining a difference between thefirst mic electrical signal and the first test signal wherein thecalibration factor β comprises a set of discrete amplitude factors atpredetermined frequency points, such that the amplitude factors can bemultiplied against a new output of the mic at the predeterminedfrequency points.

According to a tenth aspect of the embodiments, a method for calibratinga speakerphone system under test is provided, comprising; connecting acalibration unit to the speakerphone system under test (SSUT) via acommunications interface, wherein the SSUT further comprises amicrophone (mic), and mechanical vibration sensor (MVS), and wherein thecalibration unit further comprises a calibration loudspeaker; generatinga first test signal by the calibration unit and transmitting the same tothe calibration loudspeaker; broadcasting a first acoustic audio testsignal by the calibration loudspeaker; generating a first set ofmechanical vibrations in response to the first acoustic audio testsignal in the SSUT; and determining a calibration factor in regard tothe first test signal and first set of mechanical vibrations by thecalibration unit.

According to the tenth aspect of the embodiments the step of determininga calibration factor in regard to the first test signal and first set ofmechanical vibrations by the calibration unit comprises: receiving thefirst acoustic audio test signal at the SSUT, and generating the firstset of mechanical vibrations on an enclosure of the SSUT in response tothe received first acoustic audio test signal; receiving the first setof mechanical vibrations at the MVS; converting the first set ofmechanical vibrations by the MVS into a first MVS electrical signal; andgenerating an input-to-output transformation coefficient for mechanicalvibration signals generated by the calibration loudspeaker in regard tothe MVS (calibration factor γ), wherein the calibration factor γ isbased on a comparison between the first test signal and the first MVSelectrical signal.

According to the tenth aspect of the embodiments the step of generatingthe calibration factor γ comprises: receiving the first MVS electricalsignal at the calibration unit; comparing the first MVS electricalsignal with the first test signal; and generating the calibration factorγ based on the results of the comparison.

According to the tenth aspect of the embodiments the step of comparingcomprises: comparing the first MVS electrical signal and the first testsignal on the basis of frequency versus amplitude; and determining thecalibration factor δ as a function of amplitude versus frequency.

According to the tenth aspect of the embodiments the step of determiningthe calibration factor δ comprises: determining a difference between thefirst MVS electrical signal and the first test signal wherein thecalibration factor δ comprises a set of discrete amplitude factors atpredetermined frequency points, such that the amplitude factors can bemultiplied against a new output of the MVS at the predeterminedfrequency points.

According to the tenth aspect of the embodiments the step of determininga calibration factor in regard to the first test signal and first set ofmechanical vibrations by the calibration unit comprises: receiving thefirst acoustic audio test signal at the SSUT, and generating the firstset of mechanical vibrations on an enclosure of the SSUT in response tothe received first acoustic audio test signal; receiving the first setof mechanical vibrations at the mic; converting the first set ofmechanical vibrations by the mic into a first mic electrical signal; andgenerating an input-to-output transformation coefficient for mechanicalvibration signals generated by the calibration loudspeaker in regard tothe mic (calibration factor α), wherein the calibration factor α isbased on a comparison between the first test signal and the first micelectrical signal.

According to the tenth aspect of the embodiments the step of generatingthe calibration factor α comprises: receiving the first mic electricalsignal at the calibration unit; comparing the first mic electricalsignal with the first test signal; and generating the calibration factorα based on the results of the comparison.

According to the tenth aspect of the embodiments the step of comparingcomprises: comparing the first mic electrical signal and the first testsignal on the basis of frequency versus amplitude; and determining thecalibration factor α as a function of amplitude versus frequency.

According to the tenth aspect of the embodiments the step of determiningthe calibration factor comprises: determining a difference between thefirst mic electrical signal and the first test signal wherein thecalibration factor α comprises a set of discrete amplitude factors atpredetermined frequency points, such that the amplitude factors can bemultiplied against a new output of the mic at the predeterminedfrequency points.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects and features of the embodiments will becomeapparent and more readily appreciated from the following description ofthe embodiments with reference to the following figures. Differentaspects of the embodiments are illustrated in reference figures of thedrawings. It is intended that the embodiments and figures disclosedherein are to be considered to be illustrative rather than limiting. Thecomponents in the drawings are not necessarily drawn to scale, emphasisinstead being placed upon clearly illustrating the principles of theaspects of the embodiments. In the drawings, like reference numeralsdesignate corresponding parts throughout the several views.

FIG. 1 illustrates a speakerphone system according to aspects of theembodiments.

FIG. 2 illustrates a detailed view of the processor of FIG. 1, and othercomponents of FIG. 1, according to aspects of the embodiments.

FIG. 3 illustrates a flowchart of a method for calibrating thespeakerphone as shown in FIGS. 1 and 2 according to aspects of theembodiments.

FIG. 4 illustrates a flowchart of a method for using the speakerphone asshown in FIGS. 1 and 2 according to aspects of the embodiments.

FIGS. 5A and 5B illustrates a first and second calibration setup forcalibrating the Speakerphone of FIGS. 1 and 2 according to aspects ofthe embodiments.

FIG. 6 illustrates a speakerphone network in which two or morespeakerphones as shown in FIGS. 1 and 2 can bi-directionally communicatewith each other according to aspects of the embodiments.

FIG. 7 illustrates an example of an output from a device on thespeakerphone system in view of a test input signal that created suchoutput signal to determine one or more calibration coefficients.

DETAILED DESCRIPTION

The embodiments are described more fully hereinafter with reference tothe accompanying drawings, in which embodiments of the inventive conceptare shown. In the drawings, the size and relative sizes of layers andregions may be exaggerated for clarity. Like numbers refer to likeelements throughout. The embodiments may, however, be embodied in manydifferent forms and should not be construed as limited to theembodiments set forth herein. Rather, these embodiments are provided sothat this disclosure will be thorough and complete, and will fullyconvey the scope of the inventive concept to those skilled in the art.The scope of the embodiments is therefore defined by the appendedclaims. The detailed description that follows is written from the pointof view of a control systems company, so it is to be understood thatgenerally the concepts discussed herein are applicable to varioussubsystems and not limited to only a particular controlled device orclass of devices, such as speakerphone systems.

Reference throughout the specification to “one embodiment” or “anembodiment” means that a particular feature, structure, orcharacteristic described in connection with an embodiment is included inat least one embodiment of the embodiments. Thus, the appearance of thephrases “in one embodiment” or “in an embodiment” in various placesthroughout the specification is not necessarily referring to the sameembodiment. Further, the particular feature, structures, orcharacteristics may be combined in any suitable manner in one or moreembodiments.

LIST OF REFERENCE NUMBERS FOR THE ELEMENTS IN THE DRAWINGS IN NUMERICALORDER

The following is a list of the major elements in the drawings innumerical order.

-   100 Speakerphone System-   102 Loudspeaker-   104 Microphone (Mic)-   106 Amplifier (Amp)-   108 Low Pass Filter (LPF)-   110 Audio Processor (Can contain one or more Digital Signal    Processors (DSPs))-   112 Network (NW) Interface (IF)-   114 Network Cable/Power-over-Ethernet (PoE)-   116 Mechanical Vibrations (Vibrations)-   116′ Mechanical Vibration Electrical Signal-   116D′ Digitized Vibration Electrical Signal-   116″ Mechanical Vibration Error Signal-   116D″ Digitized Vibration Error Signal-   118 Mechanical Vibrations Sensor (MVS)-   122 Output Sound Acoustic Signal-   124 Backscatter Acoustic Sound Signal-   126 Input Sound Acoustic Signal-   126′ Input Sound Electrical Signal-   126D′ Digitized Input Sound Electrical Signal-   126″ Input Sound Error Signal-   126D″ Digitized Input Sound Error Signal-   128 Enclosure-   130 Mic Output Signal-   132 Far End Audio Signal 132-   140 MVS Output Signal-   202 Receiver, Amplifier, Filter-   204 Analog to Digital Converter (ADC)-   206 Processor/Digital Signal Processor (DSP)-   208 Speakerphone Output Signal-   300 Method for Calibrating a Speakerphone-   302-308 Method Steps of Method 300-   400 Method for Using a Speakerphone-   402-414 Method Steps of Method 400-   500 Speakerphone Calibration System-   502 Calibration Unit-   504 Calibration Processor/Memory-   506 Calibration Loudspeaker(s)-   600 Network System-   606 Internet Service Provider (ISP)-   608 Modulator/Demodulator (Modem)-   610 Wireless Router-   612. Plain Old Telephone Service (POTS) Provider-   614 Cellular Service Provider-   618 Communication Satellites-   620 Cellular Telecommunications Service Tower (Cell Tower)-   622 Internet-   626 Satellite Communication Systems Control Station-   702 Test Signal-   704 Output Signal from Device Under Test

LIST OF ACRONYMS USED IN THE SPECIFICATION IN ALPHABETICAL ORDER

The following is a list of the acronyms used in the specification inalphabetical order.

-   α Input-to-Output Transformation Coefficient for Acoustic Sound    Signals in regard to the Microphone (Mic acoustic transformation    coefficient/calibration factor)-   β Input-to-Output Transformation Coefficient for Mechanical    Vibration Signals Generated by the Loudspeaker in regard to the    Microphone (Mic vibration transformation coefficient/calibration    factor)-   γ Input-to-Output Transformation Coefficient for Acoustic Sound    Signals in regard to the Mechanical Vibration Sensor (MVS acoustic    transformation coefficient/calibration factor)-   δ Input-to-Output Transformation Coefficient for Mechanical    Vibration Signals Generated by the Loudspeaker in regard to    Mechanical Vibration Sensor (MVS vibration transformation    coefficient/calibration factor)    ADC Analog to Digital Converter    Amp Amplifier (Amp)    BT Bluetooth    DSP Digital Signal Processor (DSP)    GPS Global Positioning System    HZ Hertz    IF Interface    ISP Internet Service Provider    kHz Kilo-Hertz    LPF Low Pass Filter (LPF)    Mic Microphone (Mic)    MVS Mechanical Vibrations Sensor (MVS)    MVs Mechanical Vibrations (MVs)    NFC Near Field Communications    NW Network    PoE Power-over-Ethernet (PoE)    POTs Plain Old Telephone Service

The different aspects of the embodiments described herein pertain to thecontext of systems, methods, and modes for substantially or completelyeliminating mechanical vibration energy from the loudspeaker that isconverted to acoustical signals that can be acquired by a microphone asan error signal in the speakerphone, but is not limited thereto, exceptas may be set forth expressly in the appended claims.

For 40 years Creston Electronics Inc., has been the world's leadingmanufacturer of advanced control and automation systems, innovatingtechnology to simplify and enhance modern lifestyles and businesses.Crestron designs, manufactures, and offers for sale integrated solutionsto control audio, video, conferencing, computer, and environmentalsystems. In addition, the devices and systems offered by Crestronstreamlines technology, improving the quality of life for people whowork and live in commercial buildings, universities, hotels, hospitals,and homes, among other locations.

Accordingly, the systems, methods, and modes of the aspects of theembodiments described herein, as further embodied in the attacheddrawings, can be manufactured, marketed, and sold by CrestronElectronics Inc., located in Rockleigh, N.J.

Accordingly, the systems, methods, and modes of the aspects of theembodiments described herein, as embodied as a speakerphone thatincorporates a mechanical vibration sensor that can substantially orcompletely eliminate mechanical vibration energy from being consideredas acoustical voice sounds can be manufactured by Crestron ElectronicsInc., located in Rockleigh, N.J.

FIG. 1 illustrates speakerphone system (speakerphone) 100 according toaspects of the embodiments. Speakerphone 100 comprises an enclosure 128,and one or more of a loudspeaker 102, microphone (mic) 104, amplifier(amp) 106, filter (typically, though not necessarily, a low pass filter(LPF)) 108, audio signal processor (processor) 110 (which can, thoughmay not necessarily, be embodied as a digital signal processor (DSP)),network interface (NW IF) 112, network cable 114 (which can transmit notonly data, such as audio data to and from processor 110, but which canalso transmit power, such as, for example, in the form ofpower-over-Ethernet (PoE)), and mechanical vibration sensor (MVS) 118,arranged in the manner shown, though the same is not to be taken in alimiting manner, as other arrangements and interchangeable devices canalso be implemented according to aspects of the embodiments (forexample, one or more of amp 106, filter 108 can be included in a singledevice, along with processor 110, according to further aspects of theembodiments). Other means for powering speakerphone 100 can also beused, including one or more of a battery (which can, but does notnecessarily need to be rechargeable), and a conventional power supplypowered by 120/240 VAC. According to further aspects of the embodiments,the circuitry of elements 106, 108, and 110 can be embodied as purelydigital circuitry, purely analog circuitry, or any combination thereof.Cable 114 can connect through one of many different types of networks,including but not limited to, intranets, the Internet, local areanetworks, wide area networks, cellular and/or satellite based networks,landline based networks, and any combinations thereof, to a second, orplurality of remotely located “far end” speakerphones 100, according toaspects of the embodiments.

As briefly discussed above, loudspeaker 102, when broadcasting soundwaves, by the very nature of its operation, causes mechanical vibrations(vibrations) 116 to occur on enclosure 128. MVS 118 has been included,according to aspects of the embodiments, to detect vibrations 116, andgenerate mechanical vibration error signal 116″. Vibrations 116 areacquired by mic 104 and converted to an electrical signal, mechanicalvibration electrical signal 116′. As those of skill in the art canappreciate, mics 104 operate by receiving vibrations in the air on atransducer surface, and converting the received or acquired acousticalenergy into an electrical signal that represents a received acousticalaudio signal. Unfortunately, vibrations that occur in or on enclosure128 can also be acquired by mic 104 in a substantially similar manner;these unwanted vibrations, however, do not represent desired input soundacoustic signal 126 but an acoustical signal resulting from mechanicalvibrations 116 that can detrimentally affect the quality of the receivedaudio signal. Once received at mic 104, and converted to electricalsignals, input sound acoustic signal 126 becomes input sound electricalsignal 126′. Thus, according to aspects of the embodiments, the outputof mic 104 can also be referred to as mic output signal 130, and it isdefined, in part, as the combination of the desired input soundelectrical signal plus an un-desired mechanical vibration electricalsignal (i.e., microphone output signal 130 is a combination ofmechanical vibration electrical signal 116′ and input sound electricalsignal 126′; or 130=126′+116′).

To eliminate the effect of the undesired mechanical vibrations that havebeen converted to audio signals in mic 104, MVS 118 has been includedaccording to aspects of the embodiments. MVS 118 detects vibrations 116and converts the mechanical signal to an electrical signal, mechanicalvibration error signal 116″. According to further aspects of theembodiments, it would be preferable if the electrical output of MVS 118,mechanical vibration error signal 116″ exactly represented the output ofmic 104 due to vibrations 116. In that case, then by merely subtractingmechanical vibration error signal 116″ from Mic output signal 130 wouldresult in input sound electrical signal 126′, which would be a veryclose replication of input sound acoustic signal 126. According toaspects of the embodiments, calibration factors, discussed in greaterdetail below, can be generated that can substantially equalize the twooutputs; that is, a first factor can be applied to vibrations 116 toproduce mechanical vibrations error signal 116″ that is substantiallyequal to mechanical vibration electrical signal 116′, which itself canbe generated through the use of a second calibration factor. As those ofskill in the art can appreciate, subtraction can occur in either analogcircuitry, or digital, or a combination of both.

According to further aspects of the embodiments, however, there is anadditional factor that can be taken into account: when one or morepeople create input sound acoustic signal 126, such signal generates anoutput from MVS 118; this becomes input sound error signal 126″, asshown in FIG. 1. Thus, according to aspects of the embodiments, theoutput of MVS 118 can also be referred to as MVS output signal 140, andit is defined, in part, as the combination of input sound error signal126″ plus mechanical vibration error signal 116″ (i.e., MVS outputsignal 140 is a combination of input sound error signal 126″ plusmechanical vibration error signal 116″; or 140=126″+116″).

As briefly discussed above, loudspeaker 102, when broadcasting soundwaves, by the very nature of its operation, causes mechanical vibrations(vibrations) 116 to occur on enclosure 128. Vibrations 116 are acquiredby mic 104 and converted to an electrical signal, mechanical vibrationelectrical signal 116′. As those of skill in the art can appreciate,mics 104 operate by receiving vibrations in the air on a transducersurface, and converting the received or acquired acoustical energy intoan electrical signal that represents a received acoustical audio signal.Unfortunately, vibrations that occur in or on enclosure 128 can also beacquired by mic 104 in a substantially similar manner; these unwantedvibrations, however, do not represent desired input sound acousticsignal 126 but an acoustical signal resulting from mechanical vibrations116 that can detrimentally affect the quality of the received audiosignal. Once received at mic 104, and converted to electrical signals,input sound acoustic signal 126 becomes input sound electrical signal126′. Thus, according to aspects of the embodiments, the output of mic104 can also be referred to as mic output signal 130, and it is defined,in part, as the combination of the desired input sound electrical signalplus an un-desired mechanical vibration electrical signal (i.e.,microphone output signal 130 is a combination of mechanical vibrationelectrical signal 116′ and input sound electrical signal 126′; or130=126′+116′).

Although a detailed discussion of the operation of loudspeaker 102 isboth not needed and beyond the scope of the discussion to understand theaspects of the embodiments, a brief review will assist the reader. Asthose of skill in the art can appreciate, speakers 102 generally consistof a permanent magnet and electromagnetic coil (coil) attached to thenarrow portion of a cone shaped apparatus, which is generally verylightweight, though resilient. When a fluctuating electric current flowsthrough the coil, it becomes a temporary electromagnet, attracted andrepelled by the permanent magnet. As the coil moves, it moves the coneto which it is attached back and forth, creating output sound acousticsignal 122 that is broadcast, or pumped into the air, and backscatteracoustic sound signal 124 that is input into an interior of enclosure128. Thus, loudspeaker 102 is an electro-mechanical device that operatesto create output sound acoustic signal 122 by vibrating in accordancewith an alternating electrical signal and which can cause vibrations116. Vibrations 116 are caused by transferal of the mechanical energycreated by the moving/vibrating cone via mechanical coupling from thecone to the frame that holds the cone, and then from the frame toenclosure 128 that secures loudspeaker 102 in place. In addition, theimpact of backscatter acoustic signal 124 on enclosure 128 cancontribute to vibrations 116.

Vibrations 116 that occur on enclosure 128 are then transferred onto thetransducer surface of mic 104 through further mechanical couplingbetween mic 104 and enclosure 128. Such mechanical vibrations 116 canoccur over a wide range of frequencies, of varying energies, but suchfrequencies can include those within the audio range and be of suchenergy level as to be acquired by mic 104 and converted to an electricalsignal, mechanical vibration electrical signal 116′. Mechanicalvibration electrical signal 116′ is audio noise and unfortunately suchaudio noise is virtually indistinguishable from an electrical signalcreated as a result of input sound acoustic signal 126, i.e., inputsound electrical signal 126′. Because mechanical vibration electricalsignal 116′ is virtually indistinguishable from input sound electricalsignal 126′, the former cannot simply be filtered out in the presence ofthe latter; advanced signal processing techniques must be used, asdescribed below.

As those of skill in the art can appreciate, when a signal is convertedfrom one medium to another (e.g., an acoustic signal to an electricalsignal), there is often a transformation in amplitude, phase, andfrequency; in addition, such transformations also occur when a signal isthroughput a device within a single medium, such as a filter in regardto an electrical signal. In those latter cases, the signal too isgenerally transformed in terms of amplitude, phase, and frequency. Insome cases, such as in a electrical frequency filter, there relativelylittle change in frequency, but there can be an elimination of certainfrequencies such as in a notch filter, or a low pass filter, and thelike. In these types of frequency filters there will be some amplitudeand phase changes, though these can be minimized in some cases.

In regard to aspects of the embodiments, a transformation occurs betweeninputs to MVS 118 and mic 104 and their respective outputs. These areshown as follows:126′=126*α  Eq.1:116′=116*β  Eq.2:126″=126*γ  Eq.3:116″=116*δ  Eq.4:

In Equation 1 the coefficient α represents the amplitude, phase, andfrequency change that occurs when input sound acoustic signal 126 istransformed to input sound electrical signal 126′. In Equation 2 thecoefficient β represents that conversion of mechanical vibration 116into an electrical signal, mechanical vibration signal 116′; in Equation3 the coefficient γ represents that conversion of input sound acousticsignal 126 into an electrical signal through MVS 118, input sound errorsignal 126″; and in Equation 4 the coefficient δ represents thatconversion of mechanical vibration 116 into an electrical signal throughMVS 118, mechanical vibration error signal 116″. In all of Equations(1)-(4), the respective signal is multiplied by the coefficient.

According to aspects of the embodiments, in use, the signal output toloudspeaker 102, far end audio signal 132, is known to speakerphone 100prior to being output or broadcast by loudspeaker 102. Therefore, whendetermining what β should be, speakerphone 100 can take into account thetransformation by loudspeaker 102 of input audio signal 132 tovibrations 116, and the transformation by mic 104 of vibrations 116 tomechanical vibration electrical signal 116′. And, when determining whatδ should be, speakerphone 100 can take into account the transformationby loudspeaker 102 of input audio signal 132 to vibrations 116, and thetransformation by MVS 118 of vibrations 116 to mechanical vibrationerror signal 116″. Therefore, Equations 2 and 4 become:116′=132*β  Eq. 2′:116″=132*δ  Eq.4′:

As those of skill in the art can therefore appreciate, the presence of anoise signal, mechanical vibration electrical signal 116′, decreases theperformance of speakerphone system 100 by degrading the signal-to-noiseratio (SNR; increasing the amount of noise makes the SNR valuedecrease), among other performance attributes. As those of skill in theart can art can appreciate, a necessary feature of a speakerphone isacoustic echo cancellation. Acoustic echo occurs when acoustic energyfrom loudspeaker 102 couples into mic 104. For proper speakerphoneoperation, this loudspeaker acoustic energy must be removed. Acousticecho can be removed electronically with a digital signal processorexecuting an acoustic echo cancellation (AEC) algorithm. In a greatlysimplified explanation, the output from loudspeaker 102 (actually thesignal input to loudspeaker 102) is subtracted from the output of mic104; if distortions occurs, then a “true” subtraction is difficultand/or impossible to achieve, and some acoustic echo will occur, and thesignal that is sent to the far end will exhibit an echo, because theoutput of mic 104 will include signals that include energy thatoriginated at the far end, hence the term “echo.”

As those of skill in the art can appreciate, by its very nature,mechanical vibration 116 can be characterized as a distortion signal,and cannot be removed by an AEC algorithm. The output of mic 104, then,in the presence of mechanical vibrations 116, becomes input soundelectrical signal 126′ (the output of mic 104 resulting from input soundacoustic signal 126 being input to mic 104) plus mechanical vibrationelectrical signal 116′ (the result of mechanical coupling betweenloudspeaker 102, enclosure 128, and mic 104), as shown in FIG. 1. Ofcourse, FIG. 1 is a but a simplified version of what speakerphone 100can include, as there can two or more speakers 102, two or more mics104, and two or more MVSs 118, as well as a plurality of other circuitryto support the aforementioned articles.

According to aspects of the embodiments, therefore, it would beadvantageous to substantially or completely eliminate the effects ofvibration on the received audio signal so as to maintain or increase thefidelity thereof. According to aspects of the embodiments, speakerphone100 therefore includes MVS 118 that, when located in close proximity tomic 104, receives substantially similar mechanical vibrations 116 asdoes mic 104 and converts them into an electrical signal, mechanicalvibration error signal 116″.

Attention is now directed towards FIG. 2, which illustrates a detailedview of processor 110, and other portions of FIG. 1. According tofurther aspects of the embodiments, processor 110 receives MVS outputsignal 140 at first receiver/amplifier/filter (amplifier) 202 a. Thoseof skill in the art can appreciate that the device referred to as 202 acan be any one of the aforementioned items, any two, or all threecombined, according to aspects of the embodiments. Following amplifier202 a there is first analog-to-digital converter (ADC) 204 a, whichcreates a digitized version of MVS output signal 140, MVS output signal140D, and which is a combination of input sound error signal 126″ andmechanical vibration error signal 116″ (in their digitized form, inputsound error signal 126D″ and mechanical vibration error signal 116D″ atthe output of ADC 204 a).

Device 202 a can comprise an analog line receiver, optimized to receivean expected signal level and bandwidth from MVS 118 according to aspectsof the embodiments. In addition, device 202 a can also comprise anamplifier adapted to amplify only signals within an audio frequencybandwidth, or subset of that bandwidth. Similarly, device 202 a can alsocomprise a filter that passes only a certain, pre-specified bandwidth ofsignals, according to aspects of the embodiments. As those of skill inthe art can appreciate, all or substantially all of the signalprocessing that occurs in processor 110 can be accomplished digitally;in that case, once the analog MVS output signal 140 is received inprocessor 110, ADC 204 a would convert the analog signal to a digitizedversion first, and then the digitized version of MVS output signal 140can be filtered, amplified, and prepared for further signal processing,as discussed below.

According to further aspects of the embodiments, processor 110 receivesmic output signal 130 at second receiver/amplifier/filter (amplifier)202 b. Those of skill in the art can appreciate that the device referredto as 202 b can be any one of the aforementioned items, any two, or allthree combined, according to aspects of the embodiments. Followingamplifier 202 b there is second analog-to-digital converter (ADC) 204 b,which creates a digitized version of mic output signal 130, mic outputsignal 130D, and which is a combination of input sound electrical signal126′ and mechanical vibration electrical signal 116′ (in their digitizedform, input sound electrical signal 126D′ and mechanical vibrationelectrical signal 116D′ at the output of ADC 204 b).

Device 202 a can comprise an analog line receiver, optimized to receivedan expected signal level and bandwidth from MVS 118 according to aspectsof the embodiments. In addition, device 202 a can also comprise anamplifier adapted to amply only signals within an audio frequencybandwidth, or subset of that bandwidth. Similarly, device 202 a can alsocomprise a filter that passes only a certain, pre-specified bandwidth ofsignals, according to aspects of the embodiments. As those of skill inthe art can appreciate, all or substantially all of the signalprocessing that occurs in processor 110 can be accomplished digitally;in that case, once the analog mic output signal 130 is received inprocessor 110, ADC 204 b would convert the analog signal to a digitizedversion first, and then the digitized version of mic output signal 130can be filtered, amplified, and prepared for further signal processing,as discussed below.

According to aspects of the embodiments, the output of MVS 118 is anelectrical signal that represents the amount of vibration present onenclosure 128 resulting from loudspeaker 102 creating sounds 122, andfrom the effect of acoustic signals 126 that impact enclosure 128.Discussed briefly above were coefficients α, β, γ, and δ. While thepresence of such complex coefficients might be intuitively understood bythose having skill in the art, the determination thereof can be complex.By way on non-limiting example, a first manner can be the use of complexmathematical models. Such models can take into account the amplitude andfrequency of the sounds generated by loudspeaker 102 (or a by aperson/external speaker in the case of acoustic signals 126), thetransferal of vibrations from loudspeaker 102 or acoustic signals 126 toenclosure 128, the rigidity and shape of enclosure 128, temperature,humidity, barometric pressure, and perhaps many other variables.According to further aspects of the embodiments, however, another meansfor determining the coefficients α, β, γ, and δ is to calibrate eachenclosure using a variety of test signals.

By way of non-limiting example, and according to further aspects of theembodiments, one means for determining α, the coefficient that describesor characterizes the transfer of energy from an external sound sourcethrough mic 104, is to use an externally located loudspeaker, andgenerate one or more signals, of differing amplitude/frequencycombinations, and measure the output of mic 104 through processor 110.Such signals can be discrete tones, or a signal that sweeps throughdifferent frequency ranges, and changes or maintains a constantamplitude or any combination of signal types/amplitudes/frequencies.Such signals can be sine waves, or a plurality of different types ofwaves (triangular/square/pulse, among others), or can be white or pinknoise, as understood by those of skill in the art, and the like, amongother types and kinds of signals. Processor 110 and/or an externalcomputer can then compare the signal that was generated to the capturedoutput of mic 104 and determine coefficient α.

In a substantially similar manner, coefficient β, which is thecoefficient that describes or characterizes the transfer of energy fromloudspeaker 102 through MVS 118, can be determined by generating thesame or different types of sound signals as described above in regard tothe determination of coefficient α, outputting the same from loudspeaker102, and then the output of MVS 118 can be measured by processor 110.Processor 110 can then perform a Fourier analysis on digitized vibrationerror signal 116D″ to determine its audio frequency content. Processor110 and/or an external computer can then compare the signal that wasgenerated to the captured output of MVS 118 and determine coefficient β.

According to further aspects of the embodiments, coefficients γ and βcan be determined at the same time as coefficients α and β, orseparately. That is, because coefficient γ characterizes the effect ofan external audio signal on MVS 118, when coefficient α is determined asdescribed above, coefficient γ can also be determined, in asubstantially similar manner. Similarly, so too can coefficient δ bedetermined when coefficient β is determined.

Attention is now directed to FIG. 3, which illustrates method 300 forcalibrating speakerphone 100 according to aspects of the embodiments.Method 300 begins with method step 302, in which a user sets up thecalibration system. According to aspects of the embodiments, onenon-limiting example of a calibration system can include an audio signalgenerator, with one or more stored audio signals. Such stored audiosignals can be digital and/or analog signals, and can have a constantand/or adjustable amplitude and/or frequency content. Such signals caninclude white noise signals, pink noise signals, signals of a single ormultiple tones, or certain bandwidths, or can include swept frequencysignals, among other types. Such audio test signals can be generated andadministered by a computer controlled test set, or can be manuallycontrolled, or any combination thereof. The calibration system canfurther include one or more speakers to generate the audio test signalsthat calibrates mic 104 and MVS 118 according to aspects of theembodiments. The calibration system can further include a networkinterface that can be connected via an appropriate cable to DSP 206 viacable 114, so that the calibration system can generate an audio testsignal to be broadcast from loudspeaker 102 in speakerphone 100. Theaudio test signal generated to be broadcast from loudspeaker 102 can beof the same type to be generated to test mic 104 according to aspects ofthe embodiments. In addition, through network cable 114, the calibrationsystem can determine the calibration factors, store the same in internalmemory (not shown) associated with DSP 206, or can store the same in acentral server (not shown) that can be accessed by speakerphone 100, andthe calibration system can perform the calculations needed to generatethe calibration factors.

In method step 304, which follows method step 302, method 300 and thecalibration system generates an external audio signal as described abovethat can be used to determine calibration factors α and γ. Calibrationfactor α can be used to calibrate mic 104 when input acoustic soundsignals 126 are received by mic 104 and input sound electrical signal126′ is generated, and calibration factor γ can be used to calibrate MVS118 when input acoustic sound signals 126 are received by MVS 118 andinput acoustic error signal 126″ is generated according to aspects ofthe embodiments.

Following method step 304 method 300 proceeds to method step 306, inwhich method 300 and the calibration system generate an audio signal tobe broadcast by loudspeaker 102 according to aspects of the embodiments.When this test audio signal is broadcast, using an audio signal asdescribed above, calibration factors β and δ can be determined.Calibration factor β can be used to calibrate mic 104 when vibrations116 are received by mic 104 and mechanical vibration electrical signal116′ is generated, and calibration factor δ can be used to calibrate MCS118 when vibrations 116 are received by MVS 118 and mechanical vibrationerror signal 116″ is generated according to aspects of the embodiments.Following method steps 304 and 306 (which are interchangeable), method300 and the calibration system can store the calibration factors in amanner as described above.

According to aspects of the embodiments, there are many differentmethods for determining each of the calibration coefficients α, β, γ,and δ, and different methods can be used for different coefficients.According to further aspects of the embodiments, the calibrationcoefficients themselves can be of a single, fixed, constant value, orcan comprises a series of coefficients for use across an audiobandwidth. By way of non-limiting example, and not to be taken in alimiting or exclusive manner, a calibration factor can be determined bycomparing the output signal from mic 104, or MVS 118, to the signal thatgenerated the output of mic 104, or MVS 118 on a sub-band basis of theaudio band being used. For example, the output signal can be compared tothe input signal from f₁ to f₂, then f₂ to f₃, and so on, for the entireaudio bandwidth. The calibration coefficient, therefore, would be aseries of coefficients that is then applied against the same bands offrequencies in use. In determining the coefficient, the responses outputfrom the device in question, mic 104 and MVS 118, can be compared to theinput signal on smaller frequency increments, and then the valuesaveraged, the median value taken, or mean, or other methods can be used.

Attention is directed to FIG. 7, which, for purposes of illustrationonly for this discussion, shows an example of an output from a mic/MVSin view of an input signal that created such output signal. Line 702replicates the input signal, across the audio bandwidth; it is generatedat a 0 dB level. Line 704 illustrates an output signal from, by way ofnon-limiting example, MVS 118; line 704 is non-linear and ranges from−40 dB to −30 dB across the first sub-bandwidth being viewed. Thus, itcan be seen that the calibration coefficient needs to take into accounta “noise” signal that ranges from −40 dB to −30 dB in this particularbandwidth. According to aspects of the embodiments, the calibrationfactor for this sub-band of the audio bandwidth, can be a mid-band value(about −35 dB), an average of the endpoints, (40+30)/2=−35 dB, a mean ormedian value, or generated through some other manner of statisticalanalysis.

According to aspects of the embodiments, following calibration, thereare at least several methods of generating speakerphone output signal208 that take into account vibrations 116.

A. The first manner to determine speakerphone output signal 208 thattakes into account vibrations 116 is to ignore the calibration factors,and the effect of vibrations on mic 104 and audio on MVS 118. That is,in this case, the effect of mechanical vibrations electrical signal 116′is ignored. In this simplified case, the output of MVS 118 (MVS outputsignal 140), once converted into an electrical signal, is subtractedfrom the output of mic 104 (mic output signal 130). This then isEquation 5:Speakerphone Output Signal 208a=130−140.  Eq. 5:

B. According to aspects of the embodiments, a second, less simplifiedmethod of determining speakerphone output signal 208 b is to take intoaccount several of the calibration factors, those in regard to thespoken audio signals generated by users in proximity to speakerphone100, and vibration signals 116. In this case, and using Equation 2′ andsubstituting that for 116′, Equation 5 then becomes 

$\begin{matrix}{{{Speakerphone}\mspace{14mu}{Output}\mspace{14mu}{Signal}\mspace{14mu} 208b} = \frac{\left( {{130} - {\beta 132}} \right) - {140}}{\alpha}} & {{Eq}.\mspace{14mu} 6}\end{matrix}$

wherein, α is the input-to-output transformation coefficient foracoustic sound signals in regard to the mic 104, and β is thetransformation coefficient from far end audio signal 132 input toloudspeaker 102 to the output of mic 104, mechanical vibrationelectrical signal 116′. By measuring mic output signal 130, andsubtracting from it β132 and MVS output signal 140, and dividing by α,the output of speakerphone 100 can approximate very closely input soundacoustic signal 126 and delete the influences of vibrations 116.According to further aspects of the embodiments, other calculations arepossible.

According to aspects of the embodiments, MVS 118 can be embodied as oneor more discrete accelerometers, a MEMS integrated accelerometer, oranother mic 104 b. According to further aspects of the embodiments, aplurality of MVSs 118 can be located about enclosure 128 and theiroutputs averaged and then subtracted from digitized input sound signal126D′, which can be generated by an average of a plurality of mics 104.

Attention is now directed towards FIG. 4, which illustrates a flow chartof method 400 for substantially eliminating the effects of mechanicalloudspeaker vibrations in a speakerphone system according to aspects ofthe embodiments. Method 400 begins with optional method step 402 inwhich calibration can be performed, as described above in regard toMethod 300, to generate the transfer coefficients α, β, γ, and δ, in themanner as described above.

In method step 404 vibrations 116 and input sound acoustic signal 126are received at mic 104, and in method step 406, vibrations 116 andinput sound acoustic signal 126 are converted to input sound electricalsignal 126′ and mechanical vibration electrical signal 116′,respectively. The two signals 126′ and 116′ can be combined and outputas mic output signal 130. According to aspects of the embodiments, inmethod steps 404 and 406, the effect of vibrations 116 can be ignored ordetermined to be negligible, and in this case, mic output signal 130becomes input sound electrical signal 126′.

In method step 408 vibrations 116 and input sound acoustic signal 126are received at MVS 118, and in method step 410, vibrations 116 andinput sound acoustic signal 126 are converted to input sound errorsignal 126″ and mechanical vibration error signal 116″, respectively.The two signals 126″ and 116″ can be combined and output as MVS outputsignal 140. According to aspects of the embodiments, in method steps 408and 410, the effect of input sound acoustic signal 126 can be ignored ordetermined to be negligible, and in this case, MVS output signal 140becomes vibration error signal 116″.

In optional method step 412, method 400/system 100 can obtain far endaudio signal 132. As discussed above, audio signal 132, in conjunctionwith calibration factor β, can be used in place of vibration signal 116,as audio signal 132 creates the vibrations that originate fromloudspeaker 102.

In method step 414, according to aspects of the embodiments, method 400generates either of first speakerphone output signal 208 a, or secondspeakerphone output signal 208 b, according to either of Equations (5)or (6).

According to aspects of the embodiments, there are at least four methodsfor determining speakerphone output signal 208.

As discussed above, it can be the case that method 400/system 100neglects the contributions of vibrations on the output of mic 104 andneglects the contributions of input acoustic audio signal 126 on theoutput of MVS 118; in this first case, therefore, first speakerphoneoutput signal 208 a is determined by subtracting MVS output signal 140from mic output signal 130, or 208 a ₁=130−140=126′−116″. Firstspeakerphone output signal 208 a ₁ can then be sent to one or more farend speakerphones (not shown in the Figures), according to aspects ofthe embodiments.

According to further aspects of the embodiments, and as discussed above,it can be the case that method 400/system 100 includes the contributionsof vibrations on the output of mic 104 but neglects the contributions ofinput acoustic audio signal 126 on the output of MVS 118; in this secondcase, therefore, first speakerphone output signal 208 a is againdetermined by subtracting MVS output signal 140 from mic output signal130, but in a different manner: 208 a ₂=130−140=126′+116′−116″. Firstspeakerphone output signal 208 a 2 can then be sent to one or more farend speakerphones (not shown in the Figures), according to aspects ofthe embodiments.

According to further aspects of the embodiments, and as discussed above,it can be the case that method 400/system 100 neglects the contributionsof vibrations on the output of mic 104 but includes the contributions ofinput acoustic audio signal 126 on the output of MVS 118; in this thirdcase, therefore, first speakerphone output signal 208 a is againdetermined by subtracting MVS output signal 140 from mic output signal130, but in a different manner: 208 a ₃=130−140=126′−(116″+126″). Firstspeakerphone output signal 208 a ₃ can then be sent to one or more farend speakerphones (not shown in the Figures), according to aspects ofthe embodiments.

According to still further aspects of the embodiments, and as discussedabove, it can be the case that method 400/system 100 includes both thecontributions of vibrations on the output of mic 104 and thecontributions of input acoustic audio signal 126 on the output of MVS118; in this fourth case, therefore, first speakerphone output signal208 a is again determined by subtracting MVS output signal 140 from micoutput signal 130, but in a different manner: 208 a₄=130−140=(126′+116′)−(116″+126″). First speakerphone output signal 208aa can then be sent to one or more far end speakerphones (not shown inthe Figures), according to aspects of the embodiments.

According to still further aspects of the embodiments, in any of thefour methods described above in regard to first speakerphone output 208a (208 a ₁, 208 a ₂, 208 a ₃, and 208 a ₄), one or more of thecalibration factors α, β, γ, and δ, can be used on their respectivecorresponding signals if calibration is performed beforehand.

Alternatively, according to further aspects of the embodiments, inmethod step 410 method 400 can generate second speakerphone outputsignal 208 b, according to Equation (6), which takes into accountcalibration coefficients α and β that can be determined in regard tomethod 300, described above. To determine second speakerphone outputsignal 208 b, method 400 performs the following equation: 208b=[(130−β132)−140]/α, where signal 132 is the audio signal to be outputby loudspeaker 102 (i.e., far end audio signal 132). In thedetermination of second speakerphone output signal 208 b, thecalculation of (130−β132) essentially isolates input audio electricalsignal 126′ from mic output signal 130, as the product of β132 isessentially the same as mechanical vibration electrical signal 116′.Subtracting MVS output signal 140 eliminates the influence of both typesof vibrations as determined by MVS 118, and dividing by the transfercoefficient α yields, in essence, input audio acoustic signal 126, whichthe audio signal as received by mic 104. As those of skill in the artcan appreciate, however, the determination of transfer coefficients canbe less than perfect and therefore second speakerphone output signal 208b, as with all of the variations of first speakerphone output signal 208a ₁₋₄ is not a perfect rendition of input acoustic audio signal 126, buta very good improvement and substantially close approximation. Secondspeakerphone output signal 208 b can then be sent to one or more far endspeakerphones (not shown in the Figures), according to aspects of theembodiments.

FIGS. 5A and 5B illustrates first calibration system 500, and a secondcalibration setup, respectively, for calibrating speakerphone 100 ofFIGS. 1 and 2 according to aspects of the embodiments. In FIG. 5A thereis shown speakerphone 100 connected to calibration unit 502 via networkcable 114; As those of skill in the art can appreciate, speakerphone 100can be connected to a speakerphone network (discussed in regard to FIG.6, below), or another speakerphone directly, or to calibration unit 502,all through separate network cables 114, simultaneously, if needed.Calibration unit 502 includes calibration processor/memory device(processor) 504; processor 504 includes memory that can store thecalibration factors α, β, γ, and δ as described above, as well asdigital waveforms that can be converted to analog signals to bebroadcast by calibration speakers 506 a,b to determine such calibrationfactors. In addition, processor 504 can store the algorithms that can beused to calculate the calibration factors. Loudspeaker 506 a andloudspeaker 506 b are substantially similar except that loudspeaker 506b can be remotely located, and the programmable/stored waveform can betransmitted to it either through a wired/wireless connection, asindicated by the dashed line. In either case, the waveform can betransmitted as an analog or digital signal, and the requisite circuitrycan be located in loudspeaker 506 b needed to either receive anddemodulate a wirelessly transmitted analog/digital signal, or toreceive, via a hard wire, the waveform and again demodulate and/oramplify the waveform signal. In addition, calibration unit 502 andprocessor 504 can store a digital waveform that can be transmitted tospeakerphone 100 which will receive it, convert it to an analog signal,and then broadcast through loudspeaker 102, in the manner as describedabove, to create vibrations 116 that result in vibration electricalsignal 116′ from mic 104 or vibration error signal 116″ from MVS 118(note that the vibrations and related signals are shown in FIG. 1, andnot shown in FIG. 6), according to aspects of the embodiments.

FIG. 5B illustrates a second calibration setup for calibratingspeakerphone 100 of FIGS. 1 and 2 according to aspects of theembodiments. In FIG. 5B there is no separate calibration unit, butinstead additional software/applications can be provided in processor110 that provides substantially similar capabilities as was discussedabove in regard to processor 504 and calibration unit 502 in regard tostoring waveforms, and generating test signals. According to furtheraspects of the embodiments, however, the unit in FIG. 5B can broadcast awaveform to test mic 102 and MVS 118 (not shown) through eitherloudspeaker 102, or a second, separate loudspeaker 506 that is connectorto processor 110 (not shown) via network cable 114. As those of skill inthe art can appreciate, communications between speakerphone 100 andcalibration unit 502 (FIG. 5A) and/or loudspeaker 506 (FIG. 5B) can bevia network cable 114, or a separate dedicated line, or wirelessly,according to aspects of the embodiments.

FIG. 6 illustrates a speakerphone network in which two or morespeakerphones as shown in FIGS. 1 and 2 can bi-directionally communicatewith each other according to aspects of the embodiments.

FIG. 6 illustrates network system 600 within which the system and methodfor operating speakerphone 100 with increased mechanical vibration noiseimmunity operating in a communications networks can be implementedaccording to aspects of the embodiments. Much of the network systeminfrastructure shown in FIG. 6 is or should be known to those of skillin the art, so, in fulfillment of the dual purposes of clarity andbrevity, a detailed discussion thereof shall be omitted.

According to aspects of the embodiments, a user of speakerphone system100 can operate the same within network system 600. Network system 600comprises two or more speakerphones 100 a,b, each of which canincorporate the functionality of modem 608 and router 610, the latter ofwhich can be wired and/or wireless. According to further aspects of theembodiments, speakerphone 100 can access cellular service provider 614,either through a wireless connection (cellular tower 620) or via awireless/wired interconnection (a “Wi-Fi” system that comprises, e.g.,modulator/demodulator (modem) 608, wireless router 610, internet serviceprovider (ISP) 606, and internet 622). Further, speakerphone system 100can include near field communications (NFC), “Wi-Fi,” and Bluetooth (BT)communications capabilities as well, all of which are known to those ofskill in the art. Modem 608 can be connected to ISP 606 to provideinternet based communications in the appropriate format to end users(e.g., speakerphone system 100), and which takes signals from the endusers and forwards them to ISP 606. Such communication pathways are wellknown and understand by those of skill in the art, and a furtherdetailed discussion thereof is therefore unnecessary.

Speakerphone system 100 can also access communication satellites 618 andtheir respective satellite communication systems control stations 626for near-universal communications capabilities, albeit at a much highercost than convention “terrestrial” cellular services. Speakerphonesystem 100 can also make use of the different communication systemsusing plain old telephone service (POTS) provider 612.

The disclosed embodiments provide a system, software, and a method forsubstantially or completely eliminating mechanical vibration energy fromthe loudspeaker that is converted to acoustical signals that can beacquired by a microphone as an error signal in the speakerphone. Itshould be understood that this description is not intended to limit theembodiments. On the contrary, the embodiments are intended to coveralternatives, modifications, and equivalents, which are included in thespirit and scope of the embodiments as defined by the appended claims.Further, in the detailed description of the embodiments, numerousspecific details are set forth to provide a comprehensive understandingof the claimed embodiments. However, one skilled in the art wouldunderstand that various embodiments may be practiced without suchspecific details.

Although the features and elements of aspects of the embodiments aredescribed being in particular combinations, each feature or element canbe used alone, without the other features and elements of theembodiments, or in various combinations with or without other featuresand elements disclosed herein.

This written description uses examples of the subject matter disclosedto enable any person skilled in the art to practice the same, includingmaking and using any devices or systems and performing any incorporatedmethods. The patentable scope of the subject matter is defined by theclaims, and may include other examples that occur to those skilled inthe art. Such other examples are intended to be within the scope of theclaims.

The above-described embodiments are intended to be illustrative in allrespects, rather than restrictive, of the embodiments. Thus theembodiments are capable of many variations in detailed implementationthat can be derived from the description contained herein by a personskilled in the art. No element, act, or instruction used in thedescription of the present application should be construed as criticalor essential to the embodiments unless explicitly described as such.Also, as used herein, the article “a” is intended to include one or moreitems.

All United States patents and applications, foreign patents, andpublications discussed above are hereby incorporated herein by referencein their entireties.

INDUSTRIAL APPLICABILITY

To solve the aforementioned problems, the aspects of the embodiments aredirected towards systems, methods, and modes for substantially orcompletely eliminating mechanical vibration energy from the loudspeakerthat is converted to acoustical signals that can be acquired by amicrophone as an error signal in the speakerphone.

Alternate Embodiments

Alternate embodiments may be devised without departing from the spiritor the scope of the different aspects of the embodiments.

What is claimed is:
 1. A method for substantially eliminating the effectof mechanical vibration on an audio input to a speakerphone system, themethod comprising: receiving mechanical vibrations and an input soundacoustic signal at a microphone (mic); converting the receivedmechanical vibrations and input sound acoustic signal into an inputsound electrical signal, and outputting the same as a mic output signal;receiving mechanical vibrations at a mechanical vibration sensor (MVS);converting the received mechanical vibrations into a mechanicalvibration error signal, and outputting the same as an MVS output signal;generating a speakerphone system output signal by subtracting the MVSoutput signal from the mic output signal; and storing in memory aplurality of calibration factors, wherein the plurality of calibrationfactors comprises— α, an input-to-output transformation coefficient foracoustic sound signals in regard to the mic (mic acoustic transformationcoefficient/calibration factor), β, an input-to-output transformationcoefficient for mechanical vibration signals generated by a loudspeakerthat is part of the speakerphone in regard to the mic (mic vibrationtransformation coefficient/calibration factor), γ, an input-to-outputtransformation coefficient for acoustic sound signals in regard to theMVS (MVS acoustic transformation coefficient/calibration factor), and δ,an input-to-output transformation coefficient for mechanical vibrationsignals generated by the loudspeaker in regard to the MVS (MVS vibrationtransformation coefficient/calibration factor).
 2. The method accordingto claim 1, wherein the step of generating a speakerphone output signalcomprises: receiving the output of the MVS at a first receiver;receiving the output of the mic at a second receiver; and subtractingthe MVS output signal from the mic output signal using additionalcircuitry.
 3. The method according to claim 2, wherein the step ofsubtracting comprises: digitizing the received outputs of the firstreceiver and second receiver; and subtracting the digitized MVS outputsignal from the digitized mic output signal using a digital signalprocessor.
 4. The method according to claim 2, wherein the step ofsubtracting comprises: subtracting the MVS output signal from the micoutput signal using analog circuitry.
 5. The method according to claim1, wherein the MVS is one of a mic, an accelerometer, and amicroelectromechanical system (MEMs) integrated accelerometer.
 6. Themethod according to claim 1, further comprising: broadcasting an outputsound from at least one loudspeaker into a volume of space exterior tothat of the enclosure; and generating the mechanical vibrations on theenclosure resulting from the broadcast output sound.
 7. The methodaccording to claim 6, further comprising: broadcasting a backscattersound into a volume of space within the enclosure; and generating themechanical vibrations resulting from a combination of the output soundbroadcast externally to the enclosure and the backscatter soundbroadcast into the volume of the enclosure.
 8. The method according toclaim 1, further comprising: receiving a far end audio signal prior tobeing broadcast by the loudspeaker; and generating the speakerphoneoutput signal according to the following equation-second speakerphoneoutput signal=((MIC output signal−(β×far end audio signal))−MVS outputsignal)/α.
 9. The method according to claim 1, further comprising:converting the input sound acoustic signal into an input sound errorsignal; and outputting both the mechanical vibration error signal andthe input sound error signal as an MVS output signal.
 10. The methodaccording to claim 9, further comprising: receiving a far end audiosignal prior to being broadcast by the loudspeaker; and generating thespeakerphone output signal according to the following equation-secondspeakerphone output signal=((MIC output signal−(β×far end audiosignal))−MVS output signal)/α.
 11. The method according to claim 1,further comprising: performing bidirectional communications between afirst network interface that is part of the speakerphone and one or moreexternal devices.
 12. The method according to claim 11, wherein the stepof performing bidirectional communications comprises: communicating withan external calibration system adapted to generate the plurality ofcalibration factors.
 13. The method according to claim 12, wherein theexternal calibration apparatus comprises— a calibration loudspeaker; asecond network interface adapted to bidirectionally communicate with thefirst network interface; a processor circuit that includes a memorydevice; a communications circuit adapted to facilitate transfers of dataand commands between the processor circuit, the memory device, and thesecond network interface; and a first signal generator adapted togenerate one or more acoustic audio test signals.
 14. The methodaccording to claim 13, further comprising: generating the one or moreacoustic audio test signals by the first signal generator that isbroadcast by the calibration loudspeaker and received by the mic and theMVS, and determining the transformation coefficients α and γ by theprocessor based on data generated by the generated one or more acousticaudio test signals.
 15. The method according to claim 14, wherein thecalibration apparatus further comprises— a second signal generatoradapted to generate one or more electrical audio test signals.
 16. Themethod according to claim 15, further comprising: generating the one ormore electrical audio test signals by the second signal generator thatis broadcast by the at least one loudspeaker in the speakerphone thatgenerates test mechanical vibrations that are received by the mic andMVS; and determining the transformation coefficients β and δ by theprocessor based on data generated by the generated test mechanicalvibration signals.
 17. The method according to claim 11, wherein the oneor more external devices comprise one or more devices interconnectedwith the system by one or more of a local area network, a wide areanetwork, an Internet, a cellular communications network, a satellitecommunications network, a landline network, and a dedicated speakerphonenetwork.
 18. The method according to claim 17, wherein the one or moredevices includes one or more of a speakerphone system and a servercomputer.
 19. The method according to claim 1, wherein an output of themic in regard to an input of an acoustic sound signal is characterizedby the application of the transfer coefficient α to the input acousticsound signal, an output of the MVS in regard to an input of a mechanicalvibration signal generated by the loudspeaker is characterized by theapplication of the transfer coefficient δ to the input mechanicalvibration signal, an output of the MVS in regard to an input of theacoustic sound signal is characterized by the application of thetransfer coefficient γ to the input acoustic sound signal, and an outputof the mic in regard to an input of the mechanical vibration signalgenerated by the loudspeaker is characterized by the application of thetransfer coefficient β to the mechanical vibrations signal.